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New for October 2018: We spend a lot of time explaining to non-engineers that Microwaves101 is NOT about microwave ovens, but on this topic we make an exception. There's been a lot of buzz lately about advances in cooking technology, specifically the use of solid-state power amplifiers that can cook food with much greater control than the ubiquitous magnetron-based microwave ovens. This is a real breakthrough in technology that will change the way microwaves are used to cook food. The "old fashioned" microwave operated at a single frequency which makes for unavoidable hot spots. Solid-state microwaves will have a frequency sythesizer that can hop around in frequency, and exploit modulation to direct the energy where it will do the most good. Solid-state microwaves were enabled by wide bandgap semiconductors that were originally developed for military applicaations, such as gallium nitride. The only reason you don't own a solid-state microwave in 2018 is that the cost is still significantly higher than magnetrron-based products, where the high-power signal is provided by a vacuum tube that costs about fifteen dollars.
NXP has led the development of this new product. Here's a clip courtesy of Microwaves & RF of a solid-state oven that they demoed at IMS back in 2014:
That's all fine and good for an LED demo, but what about cooking real food? In this next video, NXP shows off their "Goji Food Solutions" to simultaneous cook different types of food:
Other companies are working on this technology:
Ampleon (the division that NXP sold in 2015) - they sell the components, and provide a downloadable white paper)
Miele (looks like this company is using NXP parts for "the Dialog oven")
Soldi-state ovens will prove to be more reliable than magnetron-based products, and won't slowly reduce power and efficiency over time. Also, that silly turntable your pot-pie rides around on will be eliminated, which removes another failure mode. Like the original "Radar Range", the solid-state version will first find its way into commercial kitchens which will help reduce the cost. It seems like we have been wating a long time to see this appliance on the show-room floor at Lowes, Sears (oops, scratch that they were killed off by inventment vultures) and Best Buy. Be patient, you will own one of these before the decade is through!